Note Frequency and Cents Converter
Convert musical notes and frequencies in twelve-tone equal temperament with your entered A4 tuning reference.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Each octave doubles frequency and each equal-tempered semitone multiplies it by the twelfth root of two. Use the logarithmic distance from A4 to find the nearest note and signed cent deviation.
f=A4×2^((MIDI−69)/12); cents=1200 log₂(f/fnearest)
Worked example
At A4=440 Hz, A4 is MIDI 69 and 880 Hz is A5. C4 is approximately 261.625565 Hz. An octave is 1200 cents.
Assumptions and input details
Twelve-tone equal temperament only; enharmonic sharp/flat names share one frequency. Uses scientific pitch notation, with C4 as middle C. Nearest supported MIDI note must be 0–127; exact half-semitone ties choose the higher note. The tuning reference is entered, not measured or forced to 440 Hz. No microphone, sound generation, instrument-specific temperament or automatic tuner is included.
References: UNSW acoustics and temperament
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
SI prefixes are explicit: for example, milli means one thousandth, micro one millionth and kilo one thousand. Changing a unit changes the interpretation of the entered number.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Calculate wave speed, frequency or wavelength from the other two. Convert units, find the period and view an illustrative normalized wave.
Calculate a real logarithm in any valid base, or raise that base to an exponent. Compare natural, binary and decimal logarithms and inspect the inverse relationship.
Convert frame counts, elapsed seconds and timecode, or measure a start/end timecode span. Select exact fractional rates and an explicit drop-frame convention.
Reserved advertising space.